Time delay fuze for a mine



Sept. 27, 1960 G. H. LEONARD 2,953,991

TIME DELAY FUzE Fo Filed May s, 1947 l s sheets-sheet 1 Sept. 27, 1960 G. H. LEONARD 2,953,991

TIME DELAY FUzE FOR A MINE Filed May 8, 1947 3 Sheets-Sheet 2 Syvum/vio@ v G. H. LEONARD TIME DELAY FUZE FOR A MINEv Sept. 27, 1960 Filed May 8, 1947 3 Sheets-Sheet 3 3 www4/t0@ @omni TIME DELAY FUZE FOR A MINE George H. Leonard, 2159 Kings Highway, Fairfield, Conn.

Filed May 8, 1947, Ser. No. 746,846

9 claims. (cl. 1oz-7s) (Granted under Title 35, U.S. Code (1952), sec. 266) The present invention relates to time-delay devices for fuzes employed to detonate the explosive charges contained in floating type mines, bombs, and similar ordnance devices adapted to be launched from an aircraft in flight. More particularly, the invention resides in improvements in my co-pending application for Time-Delay Fuze for a Mine, Serial No. 700,540, led October l, 1946, now Patent Number 2,750,890, whereby there is no possibility of the mine becoming armed prior to entry thereof into a body of water.

In the co-pending application, a fluid-filled bellows having a sealed capillary tube as an outlet therefor is employed to delay arming of the firing mechanism of the mine. Impeller driven means is used to maintain the firing means in the safe position thereof, and means under the control of the impeller driven means is employed to puncture the seal of the capillary tube as the impeller driven means nears the completion of its operation, thereby to discharge the fluid from the bellows at a predetermined rate and to permit a gradual collapse thereof whereby the firing mechanism is moved into its armed position a predetermined interval .of time after the seal has been punctured.

Thus, the screw shaft serves to lock positively the firing mechanism in its safe position prior to the launching of the mine and the fluid-filled bellows serves to maintain the mechanism in the safe position until the screw shaft has been substantially screwed out its predetermined amount and for an additional interval of time thereafter controlled by the rate of discharge of the lluid from the bellows and the extent of collapse thereof necessary to permit movement of the firing mechanism into its armed position. Accordingly, the device of my co-pending application affords a sufficient time delay under ordinary launching conditions to permit the floating mine to become fully launched in a condition of stable notation within a body of water before the mine becomes armed.

The device of the co-pending application, however, has not been found to be entirely satisfactory under certain conditions of use thereof such, for example, as when the mine is planted at such a great altitude as to cause the bellows to be punotured before the mine enters the water, in which case the mine may become fully armed within a relative short interval after entering the water and before reaching a condition of stable flotation therein, thus rendering the mine susceptible of being -red in response to premature actuation of the intertia firing lmechanism therefor.

The aforementioned difficulty of the device of the copending application has been obviated in the arrangement of the fuze of the present invention by the provision of means for delaying puncturing of the bellows until the mine strikes the surface of the water whereby arming of the fuze is delayed for an interval of time sufficient to enable the mine to reach a state of floating equilibrium within the water thereby to obviate danger of a premature explosion thereof.

The foregoing arrangement makes possible the use of Patented Sept. 27, 1960 a more sensitive inertia responsive tiring mechanism which is characterized by the ability to discriminate against movement of the mine in response to moderate wave action thereon and further characterized by extreme sensitivity to a lateral shock such, for example, as is received by the mine upon impact with a vessel and prior to arming of the fuze during the launching operation of the mine.

An object of the present inventionv is to provide a new and Y.improved fuze for a oating mine adapted to be planted from an aircraft in ight.

Another object is to provide a new and improved fuze for a floating mine in which the arming operation of the fuze is completed in predetermined time delayed relation to the entrance of the mine into the water. t

Another object is to provide a new and improved fuze for a floating mine in which the time delay interposed in the arming operation of the fuze is initiated as the mine enters a body of water and the arming operation is completed a predetermined period of time thereafter.

Another object is to provide a fuze for a mine having a time delayed arming means adapted to beset in operation by the force of impact of the mine with the surface of the water and adapted to delay arming of the fuze for an interval of time thereafter of suflicient duration to permit the mine to come to a condition of stable buoyancy before the arming operation is completed.

Still another object is to provide a new and improved inertia firing device for a fuze for a mine which is insensitive to normal motion of the mine caused by waves and tides and which is highly sensitive to a lateral shockV Y f received upon impact of the mine floating body.

A further object is to provide a highly sensitive inertiay ring device for use in a fuze for a floating mine adapted to be launched from an aircraft in Hight and to provide additional means for preventing arming of the device during handling and shipping of the mine and prior to launching thereof within a body of water.

A still further object is to provide a fuze for an aircraft planted floating mine in which the inertia tiring means is held against kdisplacement for an interval of time suiprior to entering a body of water;

cient to insure that the launching operation has been completedand the mine has come to a condition of substantially stable flotation within a body of water.

A still further object is to provide a fuze for a floating mine having a highly sensitive inertia firing means in which the detonator cap of the fuze is held out of operative alignment with the explosive element thereof until a predetermined period of time has elapsed after tlle'mine has entered a body of Water.

A further object resides in the provision of a fuze having impeller means responsive to the motion of the mine 9 through the air for initiating operation of a uid filledV timing mechanism as the mine strikes the surface of the water.

An additional object is to provide a new and improved fuze of the aforedescribed character which is strong, durable, safe in handling, reliable in use, and economical to manufacture.

Other objects, features, and advantages of the present invention will be apparent from the following specification, taken in connection with the accompanying drawings, in which:

Fig. `l is a vertical sectional view of a fuze according to a preferred embodiment of the present invention, the mechanism thereof being shown in its safe position prior to the launching of the mine;

Fig. 2 is a fragmentary sectional view of the lower portion of the fuze showing the impeller and associated mechanism in the position it assumes after launching and with a ship or othery Fig. 3 is a sectional view similar to Fig. 1 and showing the device in the fully armed position;

Fig. 4 is a sectional view taken along line 4-4 of Fig. l;

Fig. 5 is a sectional view taken along line 5-5 of Fig. l;

Fig. 6 is a sectional view taken along line 6-6 of Fig. l;

Fig. 7 is a sectional view taken along line 7 7 of Fig. 1;

Fig. 8 is a detail perspective View of the puncturing device, and

Fig. 9 is a sectional view taken along line 9-9 of Fig. 3.

Referring now to the drawings in which like reference characters indicate like parts throughout the several views, there is provided the usual mine case y10 having contained therein a main explosive charge 11. Threadedly engaged in one end of the case 10 is the adapter 12, which, in turn, threadedly receives the fuze indicated generally at 13. The casing of fuze 13 comprises a cylindrical member 14 having threaded in one end thereof a casing Imember 15. A plug 16 is threaded into the outer end of member 15. Fluid-tight gaskets 17, 18 and 19 are positioned between the members 10 and 12, 12 and 15, and and 16 respectively for the purpose of excluding moisture from the interiors of the mine case 10 and the fuze 13.

The plug 16 has a partially screw-threaded central bore 21, the unthreaded or smooth portion thereof forming a shoulder as at 22. The bore 21 is adapted to receive the feed screw portion 23 of a shaft 24. Rotatably mounted on the shaft 24 is a hanged bearing member 25. Secured to the bearing member 25 by a pair of diametrically opposed pins 26 is a cover 28. One of the pins 26 acts as a pivot for a planetary pinion 29, while the other pin supports a counterweight 31. A hub member 32 is mounted on bearing member 25 and' is held against axial displacement therefromby means of a locking ring 33 set in complementary grooves in the members 25 and 32. Pins 34 secure the impeller 35 to hub 32 and also project through bores in the flange of bearing member 25 thereby locking together the impeller, hub, and bearing member for mutual rotation.

A pair of diametrically opposed bores 36 in plug 16 accommodate rods 37 mounted on disk 38. Gear 39 is secured to disk 38 by means of shea-r pins 41 which prevent rotation of the gear 39 until the pins are sheared.

A shear pin 42 is set in a transverse bore in shaft 24 and rotates in recess 43 of disk 38, thereby rotatably conning the foregoing impeller mechanism to the end portion of shaft 24 between shear pin 42 and screw 27 and washer 30 secured to the end of the shaft.

A gear 44 is mounted for rotation with shaft 24 as at 45. Gears 39 and 44 mesh with planetary pinion 29 and have a tooth differential of one. Therefore, when pinion 29 makes a revolution about the xed gear 39, gear 44 rotates shaft 24 the distance of one tooth. It will, therefore, be apparent that gears 39 and 44 and pinion 29 act as a reduction gearing for driving shaft 24 at a reduced rate of rotation with respect to the speed of rotation of impeller 35.

One of the bores 36 has a lateral extension 45 which receives a spring and cup, 46 and 47 respectively. 'A ball 48 is urged by spring 46 against one of the rods 37 for a purpose to appear more fully hereinafter.

Positioned' within a recess 49 formed in the bellows base 51 is a puncturing element indicated generally at 52 and having a ange 53 at one end and a sharpened puncturing knife 54 at the other end thereof.

A bore 50 in casing member 15 receives the bellows base 51 which has secured thereto one end of each of the inner and outer bellows 55 and 56, the other end of both bellows being secured to a disk 57. The chamber 58 formed by parts 51, 55, 56 and 57 is lled with any suitable fluid having a viscosity substantially unaffected by temperature changes.

A bore 59 is formed in base 51 and receives a tapered fluid sealing and filler plug 61, the bore 59 being a convenient means of permitting the chamber 58 to be lled with fluid. The base 51 also has a bore 62 formed therein, the reduced end of which receives a capillary tube 63. A length of the tubing 63 is formed in a coil intermediate the bellows 55 and 56 and within the chamber 58. The opposite end of bore 62 is enlarged to receive a thin metallic sealing cap 64.

The knife 54 of the aforementioned puncturing element 52 is positioned in alignment with sealing cap 64. At a point intermediate its length the puncturing device 52 is provided with a threaded bore 69 for engagement with the feed screw portion 23 of shaft 24.

Shaft 24 extends into the bellows 55 substantially midway of the length thereof and abuts the end of a cylindrical extension 71 of disk 57. By means of this arrangement, the pair of bellows 55 and 56 are maintained mechanically in the expanded or safe position thereof. This position is also maintained by the uid in chamber 58. Thus the bellows are initially locked in their extended positions by both mechanical and fluid means, which arrangement renders the fuze safe prior to complete arming of the mine, as will appear more fully hereinafter.

Positioned within the bore 72 of cylindrical member 14 and extending into bore 50 of casing member 15 is a cup-shaped device 73. The device 73 is held against disk 57 by spring 74, the other end of which bears against.

shoulder 75 of bore 72.

Resting in a depression 76 in the closed end of cup member 73 is a disk 77 having an axial orice 78. Positioned against disk 77 is an inertia member 79 formed with an axial bore 81 having a reduced portion 82. A rod 85 having a head 86 at one end thereof and an enlargement 87 at the other end extends through orifice 78 and bore 81 into reduced portion 82 thereof and extends on the other side of disk 77 through an orifice 83 in cup 73 into bore 84 of disk 57. Slidably arranged on rod 85 is a tube 88 having a tapered head 89. A spring 91 is positioned about the tube 88 and bears at one end thereof against head 89 and at the other end against head 86 of rod 85.

A ball retaining member 92 bears against the upper end of inertia member 79. Positioned between head 86 and extension 93 of member 92 and within reduced bore 82 is a ball 94.

Bore 72 has a reduced threaded portion 95 for the reception of a threaded'ring 96. Bore 72 is further reduced at 97 to receive a firing pin sleeve 98. Sleeve 98 has a web 99 which is forced against member 92 by a spring 101 interposed between the web and bulkhead 1.17. The web 99 has an axial tubular portion 102 formed therein for Slidably receiving a ring pin 103. Interposed between a shoulder 104 on firing pin 103 and web 99 is a spring 105. Interposed between web 99 and ball retaining member 92 is a spring 106. The firing pin 103 is formed with a reduced portion 107 and a tapered portion 108 leading to an enlarged head 109 at the lower end thereof. Firing pin 103 is retained in tubular portion 102 by balls 111 set in openings 112 therein. Balls 111 bear against tapered portion 108 and the bore `110 in member 92. Bore 110 is enlarged at 113 to permit displacement of balls 11,1 to release the ring pin, as will be hereinafter more fully described.

The firing pin 103 is provided with a reduced extension 114 having a tapered end `115. Axial bore 116 is provided in bulkhead 117 of cylindricalr member 14 for the reception of extension 114.

Cylindrical member 14 has a reduced tubular portion 118 provided with a bore 1,19. Pivotally' mounted at 121 -in bore 119 is a detonator cap retainer 122. Extension 114 projects into a bore 123 in retainer 122 thereby g holding the retainer in the safe position against the opposing force of a spring 124. The retainer 122 also has a bore 125 containing detonator cap 126. A locking plunger 127 under action of spring 12S is adapted to extend into' a depression (not shown) in bulkhead 117 thereby to lock the detonator cap 126 in the armed position.

Mounted above the detonator cap retainer and within the bore 119 is a disk-shaped partition 129 having an explosive element 131 axially arranged therein. Container 132 receives a detonato'r charge 133 and is threadedly engaged in bore 119 as at 134.

In operation let it be assumed that the mine is launched at a high altitude from an aircraft in rllight. Referring to Fig. l of the drawings it will be seen that during the launching operation arming wire 135 is withdrawn from openings 136 and 137 in the iianges of plug 16 and cover 28 respectively, thereby freeing the impeller mechanism for rotation. As the mine falls through the air, the impeller 35 drives shaft 24 through the reduction gearing until feed screw 23 reaches shoulder 22, thereby locking the shaft and gear 44 against rotation whereupon pins `41 are sheared to render the impeller mechanism including gear 39 free to rotate about shaft 24.

Referring now to Fig. 2. wherein shaft 24 is shown in its locked position, it will be seen that rods 37 have been moved outwardly along the bores 36 by the movementY o'f shaft 24 and ball 48 has entered bore 36 individual thereto. It will also be seen that the feed screw 23 of shaft 24 has released for operation the puncturing de-A vice 52. The movement of the shaft has carried the entire impeller mechanism axially a substantial distance beyond its normal position. The mine is now partially armed.

By referring to Fig. 3 it will be seen that, as the mine enters the water, the force of impact with the surface of the water causes the impeller mechanism to be returned to its initial positio'n, such operation being ac companied by the shearing of pin 42. Simultaneously therewith, ball 48 is forced against puncturing device 52 by rod 37, thereby driving knife 54 through sealing cap 64 and permitting the fluid in chamber 58 to discharge through capillary tube 63. Insofar as shaft 24 has moved away from extension 71 of disk 57, the iiuid in chamber 58 is now the only means for preventing the collapse of bellows 5S and 56. Therefore, as the fluid discharges from the chamber 58, the bellows begin to collapse under the inuence of spring 74 which likewise causes cupshaped device 73 to move downwardly until the ange thereof bears against the upper end of casing member 15.

The ow of fluid from chamber 58 is restricted by the capillary tube 63. Therefore, the amount of delay after the mine enters the water until complete arming thereof is predetermined by the size of bore and the length of capillary tube 63.

As the cup-shaped device 73 moves with bellows 55 and 56, the inertia member 79, ball retaining member 92, sleeve 98 and associated parts move as a unit therewith, under action of spring 101 until the lower edge of sleeve 98 comes into contact with ring 96.

At this point, it will be seen by referring to Fig. 3 of the drawings that firing pin extension 114 has withdrawn from bore 123 of detonator cap retainer 122, thereby permitting the detonator cap 126 to swing under action of spring 124 into alignment with firing pin extension 114 and explosive element 131 where it is locked by plunger 127.

Upon further movement of the bellows 55 and 56, the inertia member 79 continues downwardly, the lip 138 thereof passes ball 94 and brings the ball into axial alignment with head 86 and extension 93. The lip finally contacts the flange 139 of head 86 at which time the inertia member is suspended by head 86 and spring 9.1. The ball 94 remains between head 86 and extension 93, the relative position of the parts being shown in Fig. 3.

The fuze is now armed, and in condition to be fired by movement of the inertia member 79 when the mine is struck a lateral blow.`

Let it be assumed that the mine is struck a lateral blow by a passing vessel. Inertia member 79 is rocked suiciently on its supporting structure including ro'd 85 about the tapered head 89 resting against disk 77 to cause dislodging of ball 94, thereby permitting spring 106 to force member 92 downwardly to release balls 111. These balls, in turn, permit spring 105 to force firing pin 103 into detonator cap 126. The cap lires explosive'element 131 which, in turn, lires the detonator charge 133 thereby firing the main charge v11 of the mine and destroying the vessel.

Referring to Fig. l it will be seen that the inertia member 79 is held positively between the bellows disk 57 and the ball retaining member 92 while in theV safe position. It will also be seen that ball 94 is held positively within the bore of inertia member 79 and between head 86 and extension 93. The ball 94 is thus prevented from being dislodged under conditions of severe shock such as may be encountered during shipping and handling.'v

While the ball 94 and inertia member 79 are rigidly held against movement while in the safe position, they become highly sensitive to lateral shock when moved to the armed l position as shown in Fig. 3, by reason'of the substan` tially point suspension at ange 1139 and pivotal support at head 89 for inertia element 79 in relation to the large mass thereof. Therefore, moderate movement of the mine in the water due to tide and wave actio'n may cause slight pivotal movement of the inertia element.

manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

What is claimed as new and desired to be lsecured by Letters Patent of the United States is:

l. In a fuze for a marine mine having a main explosive charge and yadapted to be Alaunched from an aircraft in Eight, the combination of detonating means for the explosive charge, a detonator cap rfor tiring said detonating means, a spring urged firing pin vadapted to strike said `detonator cap forcibly when the pin is released from a retracted position, means for normally retaining the tiring pin in the retracted position, collapsible iluid-lled bellows, a cup-shaped member adapted to be yieldably urged against said bellows and having a central opening in the bottom thereof, a disk resting'in the bottom of said cup-shaped member and having a central opening aligned with said opening in the cup,- shaped member, a rod having a anged and ,tapered head at one end thereof and extending through said openings at the other end thereof, a tubular member sleeved on said rod and having a tapered head resting on said disk, a spring interposed between theV anged head of said rod and the tapered head of said tubular member, said firing pin retaining means comprising a plurality of locking balls and a spring urged member for retaining said balls in locking position when the member is in a retracted position, a ball interposed between said tapered head of the rod and said retaining member for said balls whereby the retaining member is releasably -held in the retracted position thereof untilt he ball is dislodged, an f inertia member initially resting within said cup-shaped l In such' case, however, the head 86 moves axially under power of spring 91 toy kfollow the ball in contact therewith as the` member and having an axial bore with a lip of smaller diameter at one end thereof adapted to rest on said flange of the rod when the bellows are collapsed thereby to cause .the inertia member and the rod to be moved pivotally about the tapered head of the tubular member to dislodge said ball in response to a lateral shock received by the mine, means for puncturing the fluid-filled bellows as the mine strikes the surface of a body of water whereby fluid is causedA to ow from the bellows as the bellows are collapsed under pressure of the cup-shaped member, and means for restricting the ow of iluid from the Huidlled bellows thereby to provide a time-delay of sui-Iicent duration after the mine strikes the surface of a body of water to permit `the mine to reach a condition of stable buoyancy before the inertia member is rendered responsive to shocks received by the mine.

p 2. In a Afuze for a oating mine having a main explosive charge and adapted to be launched from an aircraft in flight, the combination of ring means Yfor the explosive charge, an inertia member having an axial bore with a reduced portion forming a lip at one end thereof, a rod adapted to be moved within said bore and having a anged and tapered head at one end thereof engageable with the ilip of said inertia member whereby the inertia member is pivotally supported on the rod, a tubular member sleeved on saidrod and having a tapered head adjacent the other end of the rod, a fluid-filled collapsible member adapted to initially render said inertia member and said firing means ineffective until the fluid-filled member is collapsed, means for puncturing said Huid-filled member as the mine strikes a body of water, a spring urgedcup-shaped member for causing the collapse of the Huid-filled member upon puncturing thereof and having means for pivotally supporting the tapered head of said tubular member, a spring interposed between the anged and tapered head of said rod and the tapered head of said tubular member thereby to provide a yieldable mounting for axial movement of said rod within said tubular member, and means including a ball mounted for rolling movement on the rtapered head of the rod for actuating the ring means when the ball rolls off the rod as the rod and inertia member pivot as a unit a predetermined amount about the tapered head of said tubular member in response to a lateral shock received by the mine.

3. In a fuze for an aircraft launched marine mine having a main explosive charge, the combination of, a detonating charge for firing said main charge, Ymeans including an inertia member having an initial safe position, an armed position, and a ring position and responsive to lateral shock for tiring said detonating charge when moved from said armed position to said ring position, means for yieldably urging said inertia member from said safe position to said armed position, a lip on said inertia member, means including a spring urged rod disposed within said inertia member in engagement with said lip for suspending and rendering said inertia member responsive to a lateral shock received by the mine, means including a fluid-lled bellows for initially maintaining said inertia member in said safe position against the urge of said yieldable means, and means responsive to the impact of the mine with a body of water for causing ow of fluid from said bellows sulicient to release said inertia member to said armed position a predetermined period of time after said impact.

4. In a fuze for an aircraft launched marine mine having a main explosive charge, the combination of detonating means for firing said main charge, inertia responsive firing means initially held in a safe position and movable to an armed position for release therefrom in response to shock to fire said detonating means, a lip formed on said inertia means, means including a spring urged rod disposed within said inertiameans in engagement with said lip for suspending and rendering said inertia means responsive to a minute lateral shock received by the mine, means for' yieldably urging said tiring means from said safe 8 position to said armed position, means including a sealed fluid-filled bellows for holding said tiring means in said safe position, and means movable by impact with the surface of a body of water to breakthle seal of said b ellows for causing the flow of fluid therefrom, said flow of fluid causing the collapse of said bellows and release of the firing means to said armed position in time delayed relation to said impact. p v

5. In a fuze for an aircraft launched marine mine having a main charge, the combination of a detonator cap for firing said charge, a spring-urged firing pin initially held in a safe position and releasable to re said cap, means for releasably holding said tiring piu in the safe position thereof, means. including an inertia member having a safe position for retaining said holding means and having an armed position for releasing said holding means when subjected to lateral shock, a lip formed on said inertia member, means including a spring urged rod disposed within said inertia member in Iengagement with said ylip for suspending and rendering said member responsive to a minute lateral shock received by the mine, a sealed uid-filled bellows independent of ambient yair and water pressures 4for initially retaining said inertia member in the safe position and having restrictive means for reducing the rate of ow of fluid therefrom when said seal is broken, and means for breaking said seal to cause ow of fluid from the bellows as the mine strikes the surface of a body of water, said restrictive means causing time delayed collapse of said bellows to release the inertia member to the armed position thereof.

6. A fuze for an aircraft launched marine mine having a main explosive charge comprising, in combination, a detonator cap for -iring said main charge, a spring-urged tiring pin normally retained in spaced relation with respect to said cap and releasable into ring engagement therewith, an inertia member having a safe position and an arm position for retaining the ltiring pin in said spaced relation, a lip formed on said inertia member, means including a spring actuated rod having a flange thereon in engagement with said lip for suspending and rendering said inertia member responsive to a minute lateral shock received by the mine, said inertia member being responsive to lateral shock for displacement from said armed position to release the firing pin into said ring engagement with the cap, sealed uid-lled bellows for holding said inertia member in the safe position thereof, means responsive to impact of the mine with the surface lof a body of water for puncturing the seal of said bellows and causing the release of -fiuid therefrom,` a capillary tube interposed between said seal and said bellows to restrict the flow of fluid from the bellows when the seal is punctured, and air-driven impeller means initially in threaded engagement with said puncturing means for retaining said puncturing means against movement with respect to said seal until the impeller means has made a suicient number of revolutions during the free flight of the mine to release the puncturing means from said threaded engagement.

7. An aircraft launched marine minehavinga main explosive charge and comprising, in (combination, detonating means for firing the explosive charge, a detonator cap mounted for movement from a safe position to an armed posit-ion with respect to said detonating means, means for yieldably urging said cap into Athe armed position, a spring-urged ring pin for releasably retainingthe cap in the safe position thereof until the pin is retracted fto an armed position and for tiring said cap when the cap is in the armed position thereof and the pin is released, ball locking means releasably retaining lsaid spring-urged pin in said safe and armed positions thereof, an inertia member having an initial safe pos-ition and an armed position, a ball member interposed between said inertia member and said locking means, and effective to releasably retain said locking means in engagement with said firing pin, said inertia member being responsive to lateral shock when in the armed position thereof to dislodge sald ball member to release the ball locking means when a lateral shock of predetermined intensity is received thereby, sealed fluid-filled bellows for initially holding said inertia member and the firing pin in said safe posit-ions thereof and for releasing the tiring pin and the inertia member as the bellows collapses, spring means for moving the inertia member and retracting the firing pin to said armed positions thereof respectively as the bellows collapses, restrictive means on said bellows for causing discharge of the fluid therefrom at a predetermined rate whereby the inertia member and firing pin move into said armed positions thereof a predetermined period of time after the seal of said bellows is broken, spring means for urging the bellows into a collapsed condition as the fluid flows therefrom, initially locked means for breaking said seal, air-driven means for unlocking the breaking means during the flight of the mine, and means responsive to impact with the surface of a body of water and engageable with said breaking means for moving the breaking means to break said seal.

8. A fuze for an aircraft launched marine mine having a main explosive charge and comprising, in combination, an impeller rotatable by passage through the air during free flight of the mine, a reduction gearing driven by said impeller, a housing for said fuze having a threaded axial bore and a pair of smooth bores spaced therefrom, one of said smooth bores having a lateral bore communicating therewith, a shaft having a screw-threaded portion and driven by said gearing, said threaded portion being mounted in said threaded bore of the fuze housing for axial movement outwardly of said housing as the shaft is rotated, a disk Xed against rotation and movable axially with said shaft, a pair of diametrically opposed pins secured at one end thereof to said disk and extending into said smooth bores, a spring-urged ball mounted in said lateral bore and initially engaging the side of one of said pins, a sealed fluid-filled bellows mounted in said housing and having a xed end and a movable end, an inertia member normally held in a safe position by the movable end of said bellows and movable to an armed position when released by the bellows as the bellows is collapsed, detonator means for firing said main charge, means including a ring pin for ring said detonator means, means controlled by the inertia member for operating said flring pin when the inertia member responds to a lateral shock received by the mine, a puncturing bar initially threadedly maintained in locked posit-ion on the threaded portion of said shaft at the inner end of said bores and held against rotary motion, a part of said threaded portion of the shaft initially extending inwardly a predetermined distance beyond said puncturing bar and movable to release the puncturing bar as the shaft is rotated, the impeller, gearing, disk, and pins forming a unit and moving outwardly away from the housing a predetermined distance as the shaft is rotated, a shear Vpin passing through the shaft and engaging said disk for moving said unit outwardly with'the shaft, said ball moving out into one of the smooth bores asl the inner end of the pin thereinpasses said lateral bore,'said unit being moved toward the housing as the shear pin is sheared by the impact of the mine striking the surface of a body of water, said impact causing one of said pins to move said ball against the puncturing bar to puncture the seal of the bellows and to cause the ow of uid therefrom whereby the bellows is collapsed to arm the inertia member.

9. A fuze for an aircraft launched marine mine having a main explosive charge and comprising, in combination, detonating means for ring said main charge, initially unarmed means for ring said detonating means, means for yieldably urging said initially unarmed means to the armed position, an impeller driven screw shaft for positively retaining said initially unarmed means in the unarmed position thereof until a period of time has elapsed during the free flight of the mine after launching, sealed huid-filled bellows for retaining said initially unarmed means in the unarmed position thereof and to release said Y initially unarmed means to an armedposition thereof when the bellows is collapsed, means responsive to the impactY v of the mine with the surface of the water for puncturing the bellows to discharge the fluid therefrom, restrictive means for limiting the discharge of the bellows to a predetermined rate whereby the bellows is collapsed a predetermined period of time-after the impact of the mine with the surface of a body of water, means including an Yinertia member having a lip formed thereon and responsive to lateral shock for operating said initially unarmed means when 4in the armed position thereof to tire the detonator means, and means including a spring urged rod disposed within said inertia member in engagement with said lip for suspending and rendering said inertia member re sponsive to said lateral shock received by the mine.

References Cited in the le of this patent UNITED STATES PATENTS FOREIGN PATENTS Y i 558,570 Great yBritain tunen, 1944 

